Florida’s Wetlands and Wildlife HealthMarilyn G. Spalding, Department of Infectious Diseases and Pathology,

College of Veterinary Medicine, University of Florida, Gainesville, Florida

Aquatic birds

• Loons and grebes• Tubenoses• Pelicaniformes• Anhingas and

cormorants• Wading birds• Swans and geese• Ducks• Raptors• Cranes• Shorebirds

• Terns• Alcids• Kingfishers• Dippers

Black Skimmer, Photo Image # BLSK 177What a fascinating and graceful bird to watch, asthis photo shows an adult Black Skimmer flyingwith its knife-edged lower mandible submergedin the water. When this Black Skimmer feels

something in the water when it's skimming, it willsnap its head down and hopefully clamp onto a

fish.Return to Birds of the Wetlands

ANIMALHEALTH

DISEASE AGENT ENVIRONMENT

HOST

ANIMALHEALTH

DISEASE AGENT

ENVIRONMENTALALTERATION

HOST

ENVIRONMENT

Human Alteration of the Environment

•TOXIN CONTAMINATION - mercury, antibiotics, pesticides, immunosupression

•NUTRIENT CONTAMINATION/ATTRACTIVE NUSIANCE –eustrongylidiosis, AVM?, Red tide/eustrongylidosis, spray fields, landfills,

•CHANGE FOOD RESOURCES – peanut toxicosis, Newcastle disease, aviancholera, immunosupression

•TRANSLOCATE ANIMALS and/or PATHOGENS – WNV, HPAI, SARS

• STRUCTURAL HAZARDS – powerlines, roads, boat use, vehicles, etc.

•LOSS OR ALTERATION OF WETLANDS- resulting in:

Crowding, relocation, diet change, nesting habitat loss, exposure to new species,habitats- HPAI, EEE, SARS

Contaminants in water

• Nutrients• Methyl mercury• Chlorinated hydrocarbons, PCBs, Dioxins,• Sodium chloride• Antibiotics• Estrogen

Current Mercury Exposure in Everglades

• ↓ PCV• ↓ Lymphoid tissue• ↓ Appetite/Motivation to hunt• ↓ Weight• Changes in tissue enzymes• Thermoregulation change• Lethargy• Decreased immune function

Nutrient contaminants

• Eustrongylidosis, and other parasites• Biotoxins? – red tide, botulism• Attractive nuisance

Eustrongylidosis• Nematode parasite ofherons & cormorants

• Complex life cycle

3

6

8

1

2

5

4

7

Eustrongylides ignotus

+nutrients

Contaminant:nutrients(sewage)Attractivenuisance

Eustrongylidosis• Cycle driven byaddition ofnutrients to water

• Kills up to 80% ofyoung birds in nest

Infectious diseases• Fecal contamination, Escherichia coli,

Campylobacter, Salmonella, Shigella

• Avian cholera

• Salmonellosis

• Newcastle Disease – aquaculture/cormorants

• Avian influenza– Most benign, HPAI

Avian influenza A• Waterbirds are natural reservoirs.Asymptomatic birds are frequently infectedwith multiple strains of virus.

• Transmission fecal oral/contamination ofwater

Domestic-wildspecies contact

MigrationTransportation

of products

High pathogenic avian influenza• High pathogenic avian

influenza (rare) may betransmitted to wild birds bycontact with domestic ducksand chickens and theirwaste and vise versa

• Spread by chicken productsand/or wild bird migration

• Fatal disease in wild birds,chickens, waterbirds,mammals, and humans

Newcastle disease• Highly contagious viral enteric or neurologic

disease

• Transmission by aerosol or fecal ingestion

• Transported by carrierbirds

• Causes reduced eggproduction to rapiddeath

Aquaculture-increasedpopulation

density

Migration

Newcastle disease virus• Access to abundant food (catfish

and crayfish aquaculture) in gulfstates increases population size

• Increased colony size andexposure of nestlings to virus

• Mortality especially of young birds

• Adult carrier birds are threat topoultry industry

Biotoxins

• Avian vacuolar myelinopathy?• Botulism• Red tide• Domoic acid• Other harmful algal biotoxins (HAB’s)• Mycotoxins

Avian vacuolar myelinopathy (AVM)• Unidentified toxin biotoxin producesdisorientation and brain lesions in coots andeagles at certain lakes in the southeast

• Recent “emerging” disease

T. Augspurger, USFWS

Whaleimages.com

Exoticweed,

nutrientpollution,Toxin?

Avian vacuolar myelinopathy (AVM)• Aquatic nutrient pollution

increases mats of highlyinvasive exotic Hydrillawhich harbors a toxinproducing organism

• Coots ingesting Hydrillabecome disoriented andare eaten by eagles

?

T. Augspurger, USFWS

Whaleimages.com

Translocation of pathogen/host

• West Nile Virus• Malaria

West Nile Virus• Example of translocation of a disease

• Common in Eurasia with occasional outbreaks, rare bird mortality

• Transmitted by mosquitoes

• Entered North America for first time in 1999 causing over 500human deaths

• Extensive mortality in somebird species especially Corvids and hawks

• With time, immunitydevelops, similar to Europe

Wetland loss – crowding

• Increased exposure to sick birds– Ie avian cholera

• Exposure to novel species (and their diseases)• Increase chance of dead bird starting botulism epizootic• Decrease in water quality

– Fecal contamination – clostridium, salmonella

• Very rapidly reproducing bacteria:Pasteurella multocida

• Fecal contamination of water which isaerosolized when birds take off from water

Avian cholera

Fewerwetlands,

Artificial foodresources,

Avian cholera• Access to waste grain

increases population size

• Immune suppression may beassociated with Vit A deficientcorn diet

• Fewer wetlands availablefurther increases density

• Fecal contamination ofwetlands

• Rapid death of 10,000s ofbirds every year

Florida 2060: A Research Project of 1000 Friends of Florida

2060 Developed Lands and Permanent Conservation Lands

Developed Land

Conservation LandsPermanently Protected

•• Decreased quality habitat for foraging and nestingDecreased quality habitat for foraging and nesting•• Forces use of marginal habitats with associatedForces use of marginal habitats with associated

dangerdanger–– increase hazards, especially boatsincrease hazards, especially boats

•• Increases territorial competitionIncreases territorial competition–– Increases adult and chick mortalityIncreases adult and chick mortality–– Increased exposure to terrestrial predatorsIncreased exposure to terrestrial predators–– Decreases pair Decreases pair ““experience levelexperience level””

Wetland loss: development,Wetland loss: development,drainage, droughtdrainage, drought

61.00

62.00

63.00

64.00

65.00

66.00

67.00

68.00

69.00

1998 1999 2000 2001 2002

1

2003

2

2004

1

2005

0

2006

4

2007

1

WINTERWELL

0.5

0.7

0.9

1.1

1.3

1.5

1.7

1.9

REPROINDEX

WINTERWELL REPROINDEX

Whooping cranereproduction in Florida

• Crowding from wetland loss, development, drainage, drought• Population expansion and inadequate nutrition from agriculture and aquaculture food

availability• Pathogen exposure and nutrient pollution from human and animal waste• Movement of host and disease agents• Toxins –physiologic change and immune suppression

Emerging disease? or new opportunities?